Outcomes Associated with Mitral Regurgitation Reduction and Myocardial Work After Transcatheter Edge-to-Edge Repair of a Mitral Valve in Dogs

Transcatheter edge-to-edge repair (TEER) is a recent minimally invasive method of managing mitral regurgitation (MR) in dogs with myxomatous mitral valve disease (MMVD). As the goal of intervention is to minimize MR severity, this study aimed to determine the association between reduced MR and changes in myocardial work indices after TEER in dogs. Ten client-owned dogs with moderate-to-severe MR were enrolled in the study, and all underwent TEER with multimodal imaging guidance. Myocardial work was analyzed before and after the procedure, and the MR severity, transmitral pressure gradients, left atrial and ventricular measurements, and index of myocardial work (GWI: the total myocardial work during systole; GCW: work contributing to LV ejection; GWW: ineffective work that contributes to no forward displacement; and GWE: ratio of constructive work to total work) were calculated. TEER significantly reduced MR severity in the majority of dogs, and this MR decrease was associated with a greater efficiency of myocardial work, more constructive work, and less wasted energy. No significant negative associations of moderate post-procedure gradients with short-term clinical outcomes emerged. TEER-mediated reduction in MR improves myocardial function in dogs. However, long-term studies are also needed to examine the effects of residual MR and transmitral gradients on cardiac function and clinical outcome.